Compressed air is supplied to a pneumatic equipment such as a pneumatic cylinder from an air pressure source through a pneumatic line such as a pipe or a hose. A pneumatic circuit is formed by connecting the air pressure source and the pneumatic equipment with the pneumatic line. In order to remove droplets and dusts in the air supplied from the air pressure source to the pneumatic equipment, a filter is provided in the pneumatic circuit. When a lubricant is to be constantly supplied to the pneumatic equipment, a lubricator to inject the lubricant in the form of a mist into the compressed air is provided in the pneumatic circuit.
The filter and the lubricator are referred to as a conditioning apparatus or an FRL including a regulator which adjusts a pressure of the compressed air supplied to the pneumatic equipment. The filter has a filter bowl, that is, a vessel to capture and contain moisture, dusts, and oil components in the air supplied from the air pressure source. In the filter described in Patent Document 1, in order to remove droplets and foreign objects in the air flowing in from a primary-side port and to supply the purified air to a secondary-side port, a filter element is mounted in a collecting vessel. At a bottom part of the collecting vessel of this filter, a drain discharge mechanism for discharging the fluid accumulated inside is provided.
The lubricator has a vessel to contain a lubricant to be injected into the compressed air, and the lubricant contained in the vessel is supplied in the form of a mist to the air flowing into the secondary-side port. As described above, the vessel in which the conditioning apparatus is housed is attached to a port block having a primary-side port and a secondary-side port formed therein. Since the filter and the lubricator each have a port block, a port block which is shared including a regulator, that is, a port unit is described in Patent Document 2.